“than I” or “than me”?

I was just reading through one of the textbooks that we use here at the University of Delaware English Language Institute — Betty Azar‘s mega-best-seller, Understanding and Using English Grammar — when I saw this footnote:

In formal English, a subject pronoun follows than: He’s older than I (am). In everyday informal English, an object pronoun is frequently used after than: He’s older than me.

This made me suspicious for two reasons: “formal” and “everyday informal” English are very vague categories that I don’t find useful; and it seems unlikely to me that this advice holds up in practice.

In fact, it doesn’t. Presumably, by “formal” Azar means academic writing, so I ran a search of the academic section of the Corpus of Contemporary American English. Here’s what I found:

than I (28) than me (37)

than he (40) than him (5)

than she (20) than her (5)

(I tried to catch only instances of than I/he/she not followed by a verb — so I don’t include “than I am/say/know/believe/etc.) because the object pronoun is impossible here.)

We can see that:

Azar’s advice is not true for the first person (I/me) — academic writers use “than me” slightly more often, in fact.

However, they do seem to prefer than he/she to than him/her.

As a bonus finding, don’t believe anyone who tells you not to use I in academic writing! Exactly why there is a different pattern for the third person (he/she), I’m not sure, but scanning through the examples, it does seem that a lot of these instances are quotations, including several from the Bible, where older and more conservative grammatical forms are common.

As for the formal/informal problem: the difference is really between certain written discourses (such as academic writing) and everything else, including most spoken English. So even in a lecture, I’d expect to hear than me/him/her not I/he/she. (You can check this in COCA or MICASE if you like!)

It would also be interesting to compare the concordance hits to see if there’s a pattern behind the selection of subject vs object pronouns after than, or whether it’s a case of writer’s style. But I should get back to my reading!